Push-out type mechanical pencil



June 25, 1968 HlRoYuKl MATSUMOTO 3,389,955

PUSH-OUT TYPE MECHANICAL PENCIL Filed March 9, 1966 2 Sheets- Sheet lINVENTOR hem/W0 /WJ R50/v70 To BY www *PIM ATTORNEYS June 25, 1968HmoYuKl MATsUMo-ro 3,389,955

PUSHOUT TYPE MECHANICAL PENCIL y Filed March 9, 1966 2 Sheets-Sheet 2FIG. 6

FIG. 7

INVENToR H VUK NABU/V072? BY WA ZM/WMWATTORNEYS United States Patent O"ice 3,389,955 PUSH-OUT TYPE MECHANICAL PENCIL Hiroyuki Matsumoto,Tokyo, Japan, assigner to Dainihon Bungu, Kabu Shikigaisha, also knownas The Japan Stationery Co., Ltd., Tokyo, Japan, a corporation of JapanFiled Mar. 9, 1966, Ser. No. 532,972 Claims priority, application Japan,May 12, 1965, 40/ 36,766 4 Claims. (Cl. 401-94) ABSTRACT OF THEDISCLOSURE In conventional ever-sharp pencils of the push-out type, thecenter bore of a front metal member has a diameter which is larger thanthe outer diameter of a lead, and an arcuate leaf spring is mounted onthe inner surface thereof so that the lead, when pushed out, may not beretracted. A principal disadvantage of this arrangement lies in the factthat it is difficult to bring the lead, which is urged by said spring,into alignment with the center bore of a front metal member in the axialdirection, the lead being liable to be deflected and broken. When thelead is broken in a space in front of a chuck, a broken piece of lead inthe center bore is slightly deviated from the center at its trailing endas it is subjected to the force of the leaf spring, so that the leadingend of the lead, when pushed by the chuck, is brought out of alignmentwith the trailing end of said broken piece of lead. If this occurs, thelead will become stuck in the center bore, thereby putting the pencilout of service.

Another disadvantage is that a cap is liable to slip olf its positionand get lost while in use, since the cap which is pressed by a nger topush out the lead is merely mounted on a lead cylinder projecting out ofthe upper end of a main body.

It is an object of this invention to provide an ever-sharp pencil of thepush-out type which has a lead retraction prevention member in the forma cylinder having a plurality of longitudinal slits, said leadretraction prevention member being firmly mounted in a space between thecenter bore of a front metal member and the front end of a chuck. Thecenter bore of said lead retraction prevention member and the centerbore of said front metal member have a diameter which is substantiallyidentical with the outer diameter of the lead so that the lead cannot bedeected in the bores even if it is broken. A broken piece of lead is notdeflected but positively pushed out by the other broken piece of leadpushed by the chuck, thereby preventing the lead from becoming stuck inthe pencil.

It is another object of this invention to provide an eversharp pencil ofthe push-out type which has on the upper end of a main body a cap forpushing out the lead which never slips olf its position while in use.

One embodiment of the invention will now be explained with reference tothe drawings wherein:

FIG. l is a sectional elevation of one embodiment of this invention withthe main body and the front metal member being out away to show theinterior;

3,389,955 Patented `lune 25, 1968 FIG. 2 is an exploded elevation ofsaid front metal member;

FIG. 3 is an enlarged sectional elevation along the line A-A of FIG. l;

FIG. 4 is a view similar to FIG. 3 and showing an ever-sharp pencil ofthe conventional type;

FIG. 5 is an exploded sectional elevation of the pushdown portion of theembodiment shown in FIG. 1;

FIG. 6 is an enlarged fragmentary sectional elevation of anotherembodiment of the push-down portion, shown with a cap mounted thereon;and

FIG. 7 is an enlarged fragmentary sectional front elevation of theembodiment illustrated in FIG. 6, shown with a cap being removed.

The ever-sharp pencil illustrated in the drawings comprises a main body1 having a lead cylinder 2 inserted therein. Threadably and integrallymounted on the lower end of the lead cylinder 2 is a chuck 4 forgripping and holding a lead, said chuck 4 being urged upwardly by aspring 5. A spring rest 6 is threadably mounted in the lower end of themain body, and an annular ring 8 which abuts against an offset portionformed on the front inner surface of said spring rest 6 bears againstthe chuck 4 which is urged upwardly by the spring 5, so that a lead isgripped and held by the chuck 4.

An ever-sharp pencil of the push-out type described hereinabove is knownin the prior art. According to this invention, the portion of the springrest 6 which projects out of the main body is externally threaded at 9and is threadably received in an internally threaded rear opening 11 ofa lead retraction prevention member 10. The aforementioned annular ring8 is operatively brought into contact with the oor surface 12 thereof.There is formed in the center of said oor surface a recess 13 which isadapted to receive therein the chuck 4, said recess 13 having a centerbore 15 adapted to receive the lead 14 therein. A cylindrical body 16 ismade resilient by virtue of a plurality of longitudinal slits 17 formedtherein. The front end of said cylindrical body 16 yieldingly bearsagainst the lead 14 by proper force of resilience.

A front metal member 19 has an opening whose internally threaded rearportion 20 threadably receives therein externally threaded centerportion 18 of the lead retraction prevention member 10. The intermediateportion 21 of said opening snugly receives therein the cylindrical body16 of lead retraction member 10. The center bore 22 formed in the frontend of said front metal member 19 is in alignment with the center bore15 of the cylindrical body 16 in the axial directions.

Referring to FIG. 5, the inner surface of the upper end of the main body1 is threaded at 23 and threadably receives therein the lower end of acylindrical holder 24 having an externally threaded portion 25. A cap 26for the lead cylinder 2 has a front offset portion 27 which abutsagainst the upper end of the lead cylinder 2, and is provided with arear offset portion 29 which abuts against an internal offset portion 30of the cylindrical holder 24. It will be appreciated from the foregoingdescription that the cap 26 never slips olf its position unless thecylindrical holder 24 is removed, so that the cap will never becomelost.

In operation, pressing down the cap 26 brings the annular ring S intocontact with the floor surface 12, and

only the chuck 4 enters the recess 13 together with the lead 14. Thechuck 4, when released from its engagement with the annular ring 8,spreads apart, so that the lead stops in its forward movement. Releasinga linger from the cap 26 enables the chuck 4 to be restored to its upperposition by the biasing force of the spring 5, but the lead is preventedfrom moving backwardly by the lead retraction prevention member 10. Whenthe chuck 4 is restored to its original position, it is pressed on itsouter circumferential surface by they annular ring 8 and rmly grips andholds the lead 14. Thus, the present invention makes it possible tobring the chuck 4, the lead retraction prevention member 10 and thefront metal member 19 into alignment with one another in the axialdirection, so that the lead pushed out the chuck 4 is introduced intothe center bore 1S of the lead retraction prevention member 10 withoutbeing deflected, and thence into the center bore 22 of the front metalmember 19. The lead 14 is held so intimately in the bore that the impactof the pencil dropping from a height of several feet onto the groundwill not cause the lead to be broken within the pencil. Even if the lead14 is broken within the pencil by a great impact, broken pieces of leadwill be pushed out by the lead pushed by the chuck 4, thereby preventingthe broken pieces of lead from becoming stuck within the pencil.

The arrangement shown in FIGS. 6 and 7 may be used to prevent the capfrom being dislodged from its position on the upper end of the leadcylinder. The upper end of the main body 1 is internally threaded at 31,and a projection 32 formed on the outerv circumferential surface of thefront end of a cap 3 is adapted to threadably engage said threadedportion 31. In inserting a lead, the cap 3' is rotate to the left torelease the projection 32 from its engagement with the threaded portion31 of the main body 1 so that the cap 3 may be removed. When the cap 3is in the condition shown in FIG. 7, it is impossible for the cap 3 topush the lead cylinder in the main body even if the cap is pushed downby a iinger, for the projection 32 abuts against the outer end of thethreaded portion 31. Turning the cap 3 to the right to bring theprojection 32 into a position inwardly of the threaded portion 31 of themain body 1 as shown in FIG. 6 enables the cap 3 to freely move upwardlyand downwardly. Moreover, the cap 3 never slips oit its position becausethe projection 32 abuts against the inner end of the threaded portion 31of the main body 1.

While a preferred embodiment of the invention has been described andillustrated, it is to be understood that the invention is not limited toits precise form, and that changes may be made therein without departingfrom the scope of the invention which is deiined in the appended claims.

What is claimed as novel is:

1. In an ever-sharp pencil of the push-out type having a cylindricalmain body open at both Vends, `a lead carrying cylinder centrally andslidably positioned within'v said main body, a chuck for gripping thelead carried in the lead carrying cylinder, said chuck being secured tothe forward end `of the lead carrying cylinder, chuck closing meansmounted on the main body contiguous to said chuck whereby relativemovement between the chuck and chuck closing means causes the chuck togrip the lead, and wherein the improvement resides in the means on theother end of the main body by which the lead ca'rrying cylinder isoperated and retained Within the main body; said means comprising anoperating member slidably carried in the other end of the main body,said operating member engaging the corresponding end portion of the leadcarrying cylinder to longitudinally move it through the main body whenthe operating member is moved and stop means for retaining the operatingmember in the other end of the main body.

2. The invention as described in claim 1 and wherein the operatingmember comprises a plunger and there is provided a cylindrical capmounted on the respective end of the main body, said cylindrical caphaving a boreY aligned with the longitudinal bore of the main body, saidplunger being slidably positioned in the cap bore.

3. The invention as described in claim 2 and wherein the cylindrical capis threadedly secured to the main body and further wherein the stopmeans comprises an abutmenton the plunger adapted to cooperate with anabutment on the inner portion of the cylindrical cap to retain theplunger within the cylindrical cap.

`4. The invention as described in claim 1 and wherein the operatingmember comprises a cylindrical operator engaging the respective end ofthe lead carrying cylinder and extending beyond the open end of the mainbody and the stop means comprises cooperating stop members on the mainbody and the cylindrical operator.

References Cited UNITED STATES PATENTS 1,373,278 3/1921 Vierling et al401-67 X 1,886,371 ll/1932 Boman lOl-67 2,484,640 10/ 1949 Mustard401-67 LAWRENCE CHARLES, Primary Examiner.

